The troubled UK Border Agency faces a backlog of cases equivalent to the population of Newcastle, MPs have warned.

Missing foreign criminals, failed asylum seekers, illegal immigrants and others refusing to leave the country make up more than 275,000 cases which the agency still needs to deal with, the Commons Home Affairs Select Committee said.

Keith Vaz, the committee's chairman, said the backlog, which will take years to clear, was unacceptable, adding that the agency seems to have "acquired its own Bermuda triangle".

"Cases enter this area and very few come out - and there's no indication of when they're going to clear a very large backlog of 275,000 cases," the Labour MP said.

"This is the first time that the committee has collated all the cases at the UK Border Agency that await resolution.

"This backlog is now equivalent to the entire population of Newcastle upon Tyne."

Mr Vaz said staff at the UKBA should forfeit their bonuses until the backlog is dealt with.

"Even though this is happening, senior management at the Border Agency receive bonuses," he said.

"We believe all bonuses that they received last year should be handed back to the taxpayer until they're an organisation that carries out the intentions of Parliament and the Government."

The backlog is the size of the population of Newcastle upon Tyne

The committee said the backlog included at least 150,000 migrants illegally living in the community - 21,000 asylum cases, and 3,900 foreign offenders.

"During the course of the inquiry, we discovered another pool of cases - 150,000 cases - of people who had been told to leave the country, who are still in the country despite being refused," Mr Vaz said.

A further 57 foreign criminals who were released in 2006 without being considered for deportation have not yet been traced.

And the so-called controlled archive, used for cases where the agency has lost track of the applicant, contains 80,000 asylum applications and 21,500 immigration cases, the report said.

The agency "does not have a strong record in deporting foreign national offenders" and should set up a team to examine why the foreign criminals living in the community had not been deported and then to ensure that they are sent home, the MPs said.

In future, deportation proceedings should begin as soon as a prisoner is sentenced to speed up the process, they added.

The damning report on the agency's work between December last year and March also said the committee did not believe the Government's aim of cutting the 260,000 student visas issued each year by a quarter would benefit the UK.

Students should be excluded from the net migration figures instead, it said.

Britain would then continue to attract international students, a market worth £7.9 billion, and still be able to aim to meet Prime Minister David Cameron's pledge to cut net migration from 250,000 to the tens of thousands by 2015, the report said.

University chancellors and campaigners have urged Mr Cameron to class international students as temporary rather than permanent migrants, removing them from the figures.

But Immigration Minister Damian Green has said students staying for more than a year are not visitors and their numbers affect communities, public services and infrastructure.

A Home Office spokesman said: "This report highlights the improvements we have made to tackle the huge backlog of cases we inherited.

"Over 2,000 overstayers have recently been removed following targeted enforcement activity, foreign national offenders are being removed more quickly and we are performing well against visa processing targets.

"Talented students are welcome in the UK, but we have introduced new powers to toughen up the system, keeping out the fraudulent and unqualified while ensuring genuine students continue to benefit from our excellent educational facilities.

"The report has raised some legitimate concerns about issues that we are aware of and are already tackling."

How about we train some of our Soldiers, soon to be made redundant , they are disciplined, competent, and efficient and could quite easily do a better job than the Border Agency at Airports and tracking down illegal immigrants.